[OE-core] [PATCH] [RFC] go.bbclass: install dependencies under $GOPATH instead of $GOROOT

[Damien Riegel]

To package a go application in Yocto, one needs to also package its
dependencies to keep the build reproducible and under control. The
default install task of the go class puts the source in ${libdir}/go/src.

${libdir}/go/src is where the standard go packages resides, aka $GOROOT.
When a go package has dependencies on other go packages, they must be
located under $GOPATH, otherwise errors like this one may happen:

  Non-standard package <packagename> in standard package <packagename>

This point of this patch is to trigger a discussion on how this issue
can be tackled in Yocto. Following code is working but should not be
considered for inclusion.

Signed-off-by: Damien Riegel <damien.riegel at gmail.com>
---
 meta/classes/go.bbclass | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/meta/classes/go.bbclass b/meta/classes/go.bbclass
index 167d02e3fa..c0ed3211cd 100644
--- a/meta/classes/go.bbclass
+++ b/meta/classes/go.bbclass
@@ -111,9 +111,9 @@ do_compile_ptest_base() {
 do_compile_ptest_base[dirs] =+ "${GOTMPDIR}"
 
 go_do_install() {
-	install -d ${D}${libdir}/go/src/${GO_IMPORT}
+	install -d ${D}/gopath/src/${GO_IMPORT} ${D}${libdir}/go
 	tar -C ${S}/src/${GO_IMPORT} -cf - --exclude-vcs --exclude '*.test' --exclude 'testdata' . | \
-		tar -C ${D}${libdir}/go/src/${GO_IMPORT} --no-same-owner -xf -
+		tar -C ${D}/gopath/src/${GO_IMPORT} --no-same-owner -xf -
 	tar -C ${B} -cf - pkg | tar -C ${D}${libdir}/go --no-same-owner -xf -
 
 	if [ -n "`ls ${B}/${GO_BUILD_BINDIR}/`" ]; then
@@ -172,9 +172,21 @@ do_install_ptest_base() {
 	chown -R root:root ${D}${PTEST_PATH}
 }
 
+do_fixupdeps() {
+	gopath="${WORKDIR}/recipe-sysroot/gopath"
+	if [ -d ${gopath} ]; then
+		tar -C ${gopath} -cf - src | tar -C ${B} --no-same-owner -k -xf -
+	else
+		echo "no dependencies to fixup"
+	fi
+}
+
 EXPORT_FUNCTIONS do_unpack do_configure do_compile do_install
 
-FILES_${PN}-dev = "${libdir}/go/src"
+addtask do_fixupdeps after do_configure before do_compile
+
+SYSROOT_DIRS_append = "/gopath"
+FILES_${PN}-dev = "/gopath/src"
 FILES_${PN}-staticdev = "${libdir}/go/pkg"
 
 INSANE_SKIP_${PN} += "ldflags"
-- 
2.19.2